The present invention relates to footwear with lace fastening and a reinforced upper, to a method of manufacturing reinforced uppers for such footwear, and to the upper itself in the semi-finished form. As is well known, an item of footwear comprises basically an upper, that is, the portion which envelops the upper portion of the foot, reaching from the toe to the heel, a sole, to which the upper is fixed along its lower edge, and a so-called heel element which completes the rear portion of the footwear, actually in the heel region.
In many types of footwear the upper also has a front opening through which the foot is inserted and which is normally equipped with a protective tongue and closed by a lace by means of eyes or hooks fixed to the outer surface of the upper along the edges of the opening. Clearly, every time the footwear is laced up the upper is stressed in the region of the eyes or hooks; moreover, in the case of footwear used for certain uses, for example, for sports activities, the lacing, and hence the upper, are also stressed during normal use, again in the region of the eyes or hooks. For this reason, up to now, it has not been possible to make the upper lighter, that is, to reduce its thickness and hence its heaviness; such a reduction would in fact lead to a weakening as a result of which the areas in which the hooks or eyes are fixed would be subject to tearing or breakage. Moreover, the substantial thickness of the upper renders it less flexible in the portions which are bent and stretched alternately when the footwear is in use.
The main object of the present invention is to provide footwear uppers which are thin but which nevertheless retain characteristics of strength for the secure fixing of lacing hooks or eyes along the two edges of the opening of the footwear.
Naturally, this object should be achieved in an industrially advantageous manner.
A further object of the present invention is to provide an upper which enables the foot to be enveloped better in the resulting footwear and which permits improved articulation of the upper in the regions interposed between the fixing positions of the lacing eyes or hooks.
It has now been found and constitutes the subject of the present invention that this and other objects are achieved by footwear having an opening with lace fastening, the upper of the footwear being produced by a method for its manufacture which is characterized in that the upper material is subjected to a pressing step in which a plurality of separate areas, raised relative to the outer face of the upper and corresponding to the mounting positions of the lacing hooks or eyes, are produced, and to a step for joining at least one layer of reinforcing material to the rear face of the upper material, the reinforcing material being applied in the region of the said raised areas of the upper in which the lacing hooks or eyes are to be mounted, and preferably extending to the portions of the surface of the upper material adjacent the said raised areas.
In the preferred embodiment of the method of the present invention, the upper material, which may be natural leather or synthetic material of the types normally used for uppers, is thinner than that normally used for an upper and the reinforcing material is joined to the inner face of the upper material simultaneously with the pressing step.
The pressing step and the step for the joining of the reinforcing material are preferably performed by means of a suitably shaped die and matrix unit under an appropriate pressure and at a temperature suitable for the type of material constituting the upper.
For example, for a leather upper, the pressing temperature is of the order of 160xc2x0 C. and the pressing pressure is about 9.8-29.4 KPa (10-30 kg/cm2).
The reinforcing material in turn is usually a plastics material which has good flexibility and resistance to tension and bending, preferably in the form of fibers impregnted with resin such as, for example, polyester, acrylic, carbon or glass fibers impregnated with a thermosetting resin.
The resin is preferably selected from polyurethane and acrylic resins.
The thickness of the reinforcing material in turn is between 0.5 and 3 mm.
The rear face of the upper may be joined in other regions to other lining materials having specific properties according to the desired functions.
For example, in the toe region of the footwear, the upper may be lined with a material which confers stiffness and/or may be waterproof and/or thermally insulating. The use of thermosetting resins such as polyurethane and acrylic resins is envisaged for this purpose.
As can be appreciated from the following description of a preferred embodiment, the present invention enables the thickness of the upper to be reduced by about 30% in comparison with the thicknesses usually used, achieving a clear advantage in terms of costs.
Moreover, with the present invention, particularly in the case of uppers made of leather or of a synthetic material of considerable stiffness, the reduction in thickness achieves a greater softness which is accompanied by a greater ability of the material to bend in response to the stresses applied to the upper by the foot when the footwear is in use. This achieves greater comfort for the user which is a very important aspect for footwear in general and even more so for sports footwear.
The reinforcing material may also be applied in different thicknesses, in the sense that it may have a considerable thickness in the region of the above-mentioned areas in which the hooks or eyes are mounted and may be much thinner, but still suitable for performing a reinforcing function, in the portions of the upper in which the lacing opening is made, so as also to reinforce the upper in the area which is subject to repeated bending when the footwear is in use.